Si(0 0 1) c(4 × 2)–p(2 × 2) surface phase transitions induced by electric fields and doping

Density functional calculations on the relative stability of c(4 × 2) and p(2 × 2) reconstructed Si(0 0 1) surfaces exposed to external electric fields and charge injection are presented. Electric fields parallel to the [0 0 1] direction or electrons inserted into surface states are found to favor the p(2 × 2) over the c(4 × 2) reconstruction. This explains recent experimental findings for Si and Ge(0 0 1).